Espresso Tips No.2

We had a customer in our shop the other day having huge problems with getting a "Crema" on his espresso coffee. He had a lever machine, which means that he can adjust the pressure at which he was pushing the water through the coffee visually, and still it wasn't working.

Now assuming that the coffee was fresh and that the water was hot enough, the next factor to look at was the quality of the grind of the ground coffee.

In the first instance he felt the coffee had been too coarse, this meant that the water flooded through the coffee without much pressure being applied, and this analysis would be correct.

He then tried to regrind the coffee so that he got smaller particles, this resulted in him not being able to get any water through the coffee.

What happened?

Well if you were to draw a graph of the size of the particles after the coffee had gone through a commercial grinder you would find that they won't vary very much in size. If you went to the bother of doing a Standard Deviation curve, you would find that the spread of sizes would create a classic "bell" shape.

Now I have to be a bit careful here, because if the blades on the commercial grinder have not been set correctly or are worn, then the particle size produced might be all over the place and you will have no chance of producing a good espresso.

Getting back to the re-grinding bit. By re-grinding you create a huge number of new particle sizes, a lot of them will be like flour - result, the water can't get through the coffee, and in turn not only might you cause yourself to have a hernia, you won't create a very good espresso based drink.

The Solution !

Well this man wanted then to eliminate any doubt when it came to the grind of his coffee, so he was interested in purchasing a domestic grinder - the next minefield!

In the domestic market there are two types of grinder, those that use a "blade", and those that use a "burr".

The blade grinders sometimes just require you to keep your finger on a button until you believe you have the correct grind - virtually impossible I can tell you

Others have a timer, however although technically slightly better, a blade will never give you the particle size spread that is ideal for espresso as it is basically "beating up" the coffee, or as above regrinding it until you get an approximate size particle.

The best is the burr grinder. The grinder blades can be infinitely adjusted, the coffee only passes through the blades once and as a result the exact range of particle sizes can be achieved.

This does take some practice, and you will need to test the grind by making a few espresso until than desired crema starts to appear.

As a rule of thumb it should take between 20 and 30 seconds to make a cup of espresso coffee. This will give the water time to pick up that wonderful coffee flavour before hitting the cup.

By the way before I start writing off all blade grinders, they are fine when it comes to making coffee in a filter or French press where there is some leeway when it comes to the grind quality. However too far out and you will once again run into problems.

Finally, how much should you spend?

Well a basic blade grinder retails for around Sterling £16, something a little fancier for around £35.
The cheapest burr grinder I know of is the Bodum Antigua which retails for around £40, however for something with a good heavy motor you should expect to pay around £160.

Enjoy your coffee, it's making me thirsty just thinking about it!